diff --git a/libc/include/utmp.h b/libc/include/utmp.h
index d764227..ebf2372 100644
--- a/libc/include/utmp.h
+++ b/libc/include/utmp.h
@@ -91,6 +91,8 @@
 void setutent();
 struct utmp* getutent();
 
+int login_tty(int);
+
 __END_DECLS
 
 #endif /* _UTMP_H_ */